Paper guide mechanism of printer

ABSTRACT

A printer is provided with a printer body that includes a paper roll holder; first and second paper guides that come in contact with both end surfaces of a paper roll in the paper roll holder and prevent a positional shift of the paper roll in a central axis direction; first and second guide rails that restrict movement directions of the first and second paper guides so as to allow the first and second paper guides to slide in the central axis direction of the paper roll; and a link lever that connects the first paper guide and the second paper guide. The link lever enables the first and second paper guides to slide in conjunction with each other and to move closer to or away from each other.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a paper guide mechanism of a printer, and particularly to a slide mechanism for a pair of paper guides that keep both end surfaces of a paper roll.

2. Description of Related Art

In recent years, small printers of a type that prints a paper roll have been widely used. There are several defined sizes for the commercial paper rolls. In order to support a plurality of sizes, this kind of printer is equipped with a paper guide mechanism to allow a paper roll of any size to be properly set in a predetermined location inside the printer and be sent in a predetermined direction.

For example, Japanese Patent Application Laid-Open No. H08-2407 discloses a paper guide mechanism that allows a pair of the paper guides to move closer to or away from each other with respect to the center by connecting the pair of paper guides to one ends of a pair of guide arms, connecting the other ends of the pair of guide arms together, and sliding the other ends of the guide arms in a direction perpendicular to a slide direction of the paper guides. Japanese Patent No. 4,776,023 discloses a paper guide mechanism in which racks are formed on a pair of paper guides, and a pair of racks and pinion gears are used to allow the pair of paper guides to move closer to or away from each other. Japanese Patent Application Laid-Open No. 2013-154580 discloses a mechanism in which the sliding of a pair of paper guides is locked when a lid of a case is closed. Japanese Patent No. 4,537,541 discloses a slide mechanism for a pair of holding plates.

In the above-described conventional paper guide mechanisms, a pair of paper guides needs to move in conjunction with a pair of guide arms; or a pair of racks engages with pinion gears when one of the paper guides moves in conjunction with the other. Such a complex mechanism makes it difficult to realize a small and lightweight device.

In the conventional paper guide mechanisms, a locking mechanism, such as ratchet mechanism, is provided in order to fix the paper guides, so that the paper guides do not easily move after adjustments are made to the guide width. However, in the case of a paper guide mechanism equipped with such a locking mechanism, the locking mechanism needs to be unlocked through an operation lever or the like before the guide width is changed. Therefore, the problem is that the mechanism is complex, and that the operability is poor.

SUMMARY OF THE INVENTION

The present invention has been made to solve the above problems. The object of the present invention is to provide a printer's paper guide mechanism with a simple configuration that allows a pair of paper guides to move closer to or away from each other. Another object of the present invention is to provide a paper guide mechanism that can offer an easy operation of locking the sliding of the paper guides and an easy operation of unlocking.

To solve the above problems, a paper guide mechanism of a printer of the present invention includes: a printer body that includes a paper roll holder; first and second paper guides that come in contact with both end surfaces, respectively, of a paper roll in the paper roll holder and prevent a positional shift of the paper roll in a central axis direction; first and second guide rails that restrict movement directions of the first and second paper guides so as to allow the first and second paper guides to slide in the central axis direction of the paper roll; and a link lever that connects the first paper guide and the second paper guide, wherein the first and second paper guides engage with one end of a longitudinal side of the link lever and the other end, respectively, a central portion of the longitudinal side of the link lever is pivotally supported on the printer body via a rotation shaft, and the link lever enables the first and second paper guides to slide in conjunction with each other and to move closer to or away from each other.

According to the present invention, it is possible to realize the paper guide mechanism with a simple configuration that allows a pair of paper guides to move closer to or away from each other.

The paper guide mechanism of the present invention preferably further includes a cover that opens or closes the paper roll holder, wherein the cover includes a ratchet section that is fitted onto the first paper guide and the second paper guide when the cover is closed and fix positions of the first and second paper guides. According to this configuration, without the need to unlock a locking mechanism through an operation lever or the like, it is possible to fix the paper guides or unlock the fixing only by closing or opening the cover. Therefore, it is possible to provide the paper guide mechanism that is excellent in operability.

In the present invention, the link lever preferably includes a plate spring section, and the plate spring section engages, in a frictional manner, with an uneven surface that is located in a pressing direction thereof and is provided on a side of the printer body. This configuration enables a user to receive a click feeling when the plate spring section goes over the uneven surface. Therefore, it is possible to increase the positioning accuracy of the paper guides and the operability.

In the present invention, the first and second paper guides are preferably identical in shape, and the first and second paper guides are dyad symmetrical. According to this configuration, common parts can be used, resulting in a reduction in costs.

The paper guide mechanism of the present invention preferably further includes: a third guide rail that is disposed on an extension of the second guide rail and restricts the movement direction of the first paper guide so as to allow the first paper guide to slide in the central axis direction of the paper roll; and a fourth guide rail that is disposed on an extension of the first guide rail and restricts the movement direction of the second paper guide so as to allow the second paper guide to slide in the central axis direction of the paper roll, wherein the first paper guide includes a first fitting portion that is fitted onto the first guide rail, and a second fitting portion that is fitted onto the third guide rail, the second paper guide includes a third fitting portion that is fitted onto the second guide rail, and a fourth fitting portion that is fitted onto the fourth guide rail, the first and third fitting portions are C-shaped or O-shaped in cross section in order not to allow the first and third fitting portions to be detached in a direction perpendicular to extending directions of the first and second guide rails, and the second and fourth fitting portions are U-shaped in cross section in order to allow the second and fourth fitting portions to be attached or detached in a direction perpendicular to extending directions of the third and fourth guide rails. According to this configuration, it is possible to support the first and second paper guides in a stable manner while allowing the first and second paper guides to slide smoothly.

In the present invention, the first to fourth guide rails are preferably formed integrally with the printer body. According to this configuration, it is possible to realize the slide mechanism for the paper guides easily and at low cost.

According to the present invention, it is possible to provide a printer's paper guide mechanism with a simple configuration that allows a pair of paper guides to move closer to or away from each other. Moreover, according to the present invention, it is possible to provide a paper guide mechanism that can offer an easy operation of locking the sliding of the paper guides and an easy operation of unlocking.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view showing the configuration of a printer according to a first embodiment of the present invention;

FIG. 2 is a schematic perspective view showing the configuration of a paper guide mechanism;

FIG. 3 is a diagram showing the configuration of a frame of the printer body, and particularly, a schematic perspective view showing in detail the configuration of a bottom portion (or a surface that faces the link lever) of the printer body;

FIG. 4 is a schematic cross-sectional view of a plate spring section of the link lever taken along line X-X in FIGS. 2 and 3;

FIG. 5 is a schematic perspective view showing a connecting structure of a pair of paper guides and the link lever; and

FIGS. 6A and 6B are diagrams showing relation between the paper guide and guide rails, and particularly, FIG. 6A is a schematic perspective view, and FIG. 6B is a schematic side view.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will be explained below in detail with reference to the accompanying drawings.

FIG. 1 is a schematic perspective view showing the configuration of a printer according to a first embodiment of the present invention. FIG. 1 shows a situation where a cover is being opened.

As shown in FIG. 1, a printer 1 of the present embodiment includes a printer body 10, which includes a paper roll holder 11; a label printing unit 12, which includes a thermal head; and a cover 13, which is provided above the paper roll holder 11. The paper roll holder 11 is located in a rear portion of the printer body 10. The label printing unit 12 is provided in a front portion of the printer body 10 so as to be located ahead of the paper roll holder 11. A rotation shaft 13 a of the cover 13 is provided in a rear end portion of the printer body 10. When an unlocking button 13 b is pushed, the cover 13 is unlocked with respect to the printer body 10; the cover 13 can be opened by lifting up a front end portion of the cover 13.

The paper roll 2 is housed in the paper roll holder 11. A pair of paper guides 15L and 15R are provided on both sides of the paper roll 2 in the width direction. The paper guides 15L and 15R are in contact with the left and right sides of the paper roll 2 in order to prevent a positional shift of the paper roll in a central axis direction. In a front end portion of the cover 13, a platen roller 16 is mounted. The platen roller 16 is positioned so as to face a thermal head (not shown) of the label printing unit 12 when the cover 13 is closed.

While the details will be described later, on a back surface of the cover 13, ratchet sections 13 c are provided. When the cover 13 is being closed, upper end portions of the paper guides 15L and 15R engage with corresponding ratchet sections 13 c to ensure that the positions of the paper guides 15L and 15R are fixed.

FIG. 2 is a schematic perspective view showing the configuration of a paper guide mechanism.

As shown in FIG. 2, the paper guide mechanism includes the pair of paper guides 15L and 15R; guide rails 17 a and 17 c, which define a sliding direction of one paper guide 15L (first paper guide); guide rails 17 b and 17 d, which define a sliding direction of the other paper guide 15R (second paper guide); and a link lever 18, which connects the first paper guide 15L and the second paper guide 15R. The sliding direction of the paper guides 15L and 15R is the same as a central axis direction of the paper roll (Refer to FIG. 1).

In the present embodiment, the guide rails 17 a to 17 d are provided in a bottom of the paper roll holder 11, and are formed integrally with the printer body 10. The first paper guide 15L is mounted on the two guide rails 17 a and 17 c that are parallel to one another. The second paper guide 15R, is mounted on the two guide rails 17 b and 17 d that are parallel to one another. The first paper guide 15L includes a first fitting portion 15 a, which is fitted onto the first guide rail 17 a; and a second fitting portion 15 b, which is fitted onto the third guide rail 17 c. The second paper guide 15R includes a third fitting portion 15 c, which is fitted onto the second guide rail 17 b; and a fourth fitting portion 15 d, which is fitted onto the fourth guide rail 17 d.

The third guide rail 17 c is disposed on an extension of the second guide rail 17 b. The fourth guide rail 17 d is disposed on an extension of the first guide rail 17 a. That is, the first and fourth guide rails 17 a and 17 d appear to have been formed by splitting one guide rail in half; the second and third guide rails 17 b and 17 c also appear to have been formed by splitting one guide rail in half. The reason why the guide rails are formed in such a manner is to allow the first paper guide 15L to be fitted from the tips of the guide rails 17 a and 17 c, and to allow the second paper guide 15R to be fitted from the tips of the guide rails 17 b and 17 d, thereby making it easier to attach the paper guides to the guide rails. Accordingly, the space between the tips of the first and fourth guide rails 17 a and 17 d that face each other, and the space between the tips of the second and third guide rails 17 c and 17 b that face each other are set wider in width than the paper guides 15L and 15R.

The link lever 18 is an elongated plate made of metal or resin. The link lever 18 is placed below the paper roll holder 11. When the thin link lever 18 is disposed below the paper roll holder 11, the paper guide mechanism can be mounted without interfering with the layout of other components. As a result, it is possible to realize a compact and lightweight printer.

The first paper guide 15L engages with one end of a longitudinal side of the link lever 18. The second paper guide 15R engages with the other end of the longitudinal side of the link lever 18. A central portion of the longitudinal side of the link lever 18 is pivotally supported on the printer body 10 via a rotation shaft 18 a. The rotation shaft 18 a of the link lever 18 is located at the center of the width direction of the paper roll holder 11. It is more preferred that the rotation shaft 18 a of the link lever 18 be located at the center of a front-rear direction that is perpendicular to the width direction of the paper roll holder 11.

FIG. 3 is a diagram showing the configuration of a frame of the printer body 10. In particular, FIG. 3 is a schematic perspective view showing in detail the configuration of a bottom portion (or a surface that faces the link lever 18) of the printer body 10. FIG. 4 is a schematic cross-sectional view of a plate spring section of the link lever 18 taken along line X-X in FIGS. 2 and 3.

As shown in FIGS. 2, 3, and 4, the link lever 18 includes a pair of plate spring sections 18 b and 18 b, which are formed by partially slitting the link lever 18. While the details will be described later, projections (bosses) 18 c that are formed at the tips of the plate spring sections 18 b and 18 b engage with uneven grooves 10 a in a frictional manner; the uneven grooves 10 a are formed on a facing surface of the printer body 10. The projections 18 c are pressed against the uneven grooves 10 a by elastic force of the plate spring sections 18 b. As the link lever 18 is rotated, the projections 18 c go over peaks of the uneven grooves 10 a, thereby giving a user a click feeling when the user slides the paper guides 15L and 15R. Therefore, the user can fine-tune where the paper guides 15L and 15R are fixed.

FIG. 5 is a schematic perspective view showing a connecting structure of a pair of paper guides 15L and 15R and the link lever 18.

As shown in FIG. 5, a first engagement pin 15 e is provided below the first fitting portion 15 a of the first paper guide 15L. A second engagement pin 15 f is provided below the third fitting portion 15 c of the second paper guide 15R. The first and second engagement pins 15 e and 15 f engage with long holes 18 d (or elongated slits) that are formed in the one end of the link lever 18 and the other end. That is, the first paper guide 15L engages with the one end of the link lever 18 via the first engagement pin 15 e; the second paper guide 15R engages with the other end of the link lever 18 via the second engagement pin 15 f. As the link lever 18 is rotated, the first and second engagement pins 15 e and 15 f slide inside the long holes 18 d. In this manner, the first and second paper guides 15L and 15R are subjected only to a slide-direction force from the link lever 18.

The first and second paper guides 15L and 15R are connected via the link lever 18 as described above. Therefore, one of the paper guides 15L and 15R slides in conjunction with the other. When the first paper guide 15L slides in a direction toward the second paper guide 15R, the one end of the link lever 18 turns in the same direction as the first paper guide 15L, while the other end of the link lever 18 turns in a direction toward the first paper guide 15L. As a result, the second paper guide 15R slides in the same direction as the other end of the link lever 18. When the first paper guide 15L slides in a direction away from the second paper guide 15R, the second paper guide 15R slides in a direction away from the first paper guide 15L. In this manner, one of the paper guides 15L and 15R slides in conjunction with the other. The link lever 18 enables the paper guides 15L and 15R to move closer to or away from one another.

FIGS. 6A and 6B are diagrams showing relation between the first paper guide 15L and a pair of guide rails 17 a and 17 c. In particular, FIG. 6A is a schematic perspective view, and FIG. 6B is a schematic side view. Incidentally, the relation between the second paper guide 15R and a pair of guide rails 17 b and 17 d is identical to the relation between the first paper guide 15L and a pair of guide rails 17 a and 17 c. Accordingly, only the first paper guide 15L will be described, and the second paper guide 15R will not be described.

As shown in FIGS. 6A and 6B, a knob portion 15 g is provided in an upper end portion of the paper guide 15L so as to protrude upward. A user of the printer 1 can adjust the position of the paper guide 15L by holding the knob portion 15 g and moving the paper guide 15L. The tip of the knob portion 15 g is tapered. When the cover 13 is closed, the tip of the knob portion 15 g engages with the ratchet sections 13 c, and the position of the paper guide 15L is therefore fixed. When the cover 13 is opened, the paper guide 15L is automatically unlocked.

The paper guide 15L includes the first fitting portion 15 a, which is fitted onto one guide rail 17 a; and the second fitting portion 15 b, which is fitted onto the other guide rail 17 c. The first fitting portion 15 a is C-shaped (or O-shaped) in cross section so that the first fitting portion 15 a cannot be detached from the guide rail 17 a in a direction perpendicular to the extending direction of the guide rail 17 a; the shape only allows the first fitting portion 15 a to slide. On the other hand, the second fitting portion 15 b is U-shaped in cross section so that the second fitting portion 15 b can be attached to or detached from the guide rail 17 c in a direction perpendicular to the extending direction of the guide rail 17 c. In this manner, the paper guide 15L is fixed only to one guide rail 17 a in so to be slidable, while the paper guide 15L has play at a position where the paper guide 15L is fitted onto the other guide rail 17 c. Therefore, it is possible to support the paper guide 15L in a stable manner while allowing the paper guide 15L to slide smoothly.

As shown in FIGS. 2 and 5, the link lever 18 is provided so as to extend in a diagonal direction of the paper roll holder 11. The one end of the link lever 18 and the other end are positioned in the front and rear portions of the printer, respectively. When seen from the front side of the printer body 10, the first engagement pin 15 e of the first paper guide 15L, which is disposed on the left side, is connected to the one end of the link lever 18. When seen from the front side of the printer body 10, the second engagement pin 15 f of the second paper guide 15R, which is disposed on the right side, is connected to the other end of the link lever 18. That is, the second paper guide 15R is the equivalent of the first paper guide 15L that has turned 180 degrees. The first paper guide 15L and the second paper guide 15R are dyad symmetrical. The paper guides 15L and 15R are identical in shape and have the engagement pins in the same location. According to the configuration of the paper guides, common parts can be used, resulting in a reduction in costs.

As described above, the printer's paper guide mechanism of the present embodiment includes the link lever 18, which connects the pair of paper guides 15L and 15R. The link lever 18 enables one of the paper guides to slide in conjunction with the other. Therefore, it is possible to realize the simple paper guide mechanism that allows the pair of paper guides to move closer to or away from each other. When a user tries to change the paper guide width, the user does not have to unlock a locking mechanism through an operation lever or the like. Thus, it is possible to provide the paper guide mechanism that is excellent in operability.

It is apparent that the present invention is not limited to the above embodiments, but may be modified and changed without departing from the scope and spirit of the invention.

For example, according to the above embodiment, two guide rails are provided for one paper guide. However, two guide rails are not necessarily required. Only one guide rail may be provided for one paper guide. That is, there may be the first guide rail 17 a, which restricts the movement direction of the first paper guide 15L, and the second guide rail 17 b, which restricts the movement direction of the second paper guide 15R. Furthermore, each guide rail is not necessarily required to be formed integrally with the printer body. The guide rails may be added to the printer body later.

In the above embodiment, the first and second paper guides 15L and 15R are identical in shape. However, the first and second paper guides 15L and 15R may be different in shape.

In the above embodiment, the frictional engagement between the plate spring portion, which is formed on the link lever, and the uneven surface of the printer body gives a user a click feeling when the user slides the paper guides. However, such a structure is not necessarily required for the present invention. Other methods may be employed to produce a click feeling. 

What is claimed is:
 1. A paper guide mechanism of a printer comprising: a printer body that includes a paper roll holder; first and second paper guides that come in contact with both end surfaces, respectively, of a paper roll in the paper roll holder and prevent a positional shift of the paper roll in a central axis direction; first and second guide rails that restrict movement directions of the first and second paper guides so as to allow the first and second paper guides to slide in the central axis direction of the paper roll; and a link lever that connects the first paper guide and the second paper guide, wherein the first and second paper guides engage with one end of a longitudinal side of the link lever and the other end, respectively, a central portion of the longitudinal side of the link lever is pivotally supported on the printer body via a rotation shaft, and the link lever enables the first and second paper guides to slide in conjunction with each other and to move closer to or away from each other.
 2. The paper guide mechanism as claimed in claim 1 further includes a cover that opens or closes the paper roll holder, wherein the cover includes a ratchet section that is fitted onto the first paper guide and the second paper guide when the cover is closed and fix positions of the first and second paper guides.
 3. The paper guide mechanism as claimed in claim wherein the link lever includes a plate spring section, and the plate spring section engages, in a frictional manner, with an uneven surface that is located in a pressing direction thereof and is provided on a side of the printer body.
 4. The paper guide mechanism as claimed in claim wherein the first and second paper guides are identical in shape, and the first and second paper guides are dyad symmetrical.
 5. The paper guide mechanism as claimed in claim 1 further includes: a third guide rail that is disposed on an extension of the second guide rail and restricts the movement direction of the first paper guide so as to allow the first paper guide to slide in the central axis direction of the paper roll; and a fourth guide rail that is disposed on an extension of the first guide rail and restricts the movement direction of the second paper guide so as to allow the second paper guide to slide in the central axis direction of the paper roll, wherein the first paper guide includes a first fitting portion that is fitted onto the first guide rail, and a second fitting portion that is fitted onto the third guide rail, the second paper guide includes a third fitting portion that is fitted onto the second guide rail, and a fourth fitting portion that is fitted onto the fourth guide rail, the first and third fitting portions are C-shaped or O-shaped in cross section in order not to allow the first and third fitting portions to be detached in a direction perpendicular to extending directions of the first and second guide rails, and the second and fourth fitting portions are U-shaped in cross section in order to allow the second and fourth fitting portions to be attached or detached in a direction perpendicular to extending directions of the third and fourth guide rails.
 6. The paper guide mechanism as claimed in claim 5, wherein the first to fourth guide rails are formed integrally with the printer body. 